1. Field of the Invention
This invention relates broadly to umbilical cord clamps. More particularly, this invention relates to umbilical cord clamps which both sever and clamp the umbilical cord.
2. State of the Art
The umbilical cord serves as the conduit between a mother and a fetus developing in the womb of the mother. Nutrients and oxygen within the blood of the mother pass through the umbilical cord to the fetus. Immediately after a baby is born, the umbilical cord must be clamped to stop the flow of blood therethrough and the cord must then be severed to separate the baby from the placenta. For many years, this procedure utilized two separate clamps to clamp the cord, and a scalpel to cut the cord.
Over the past thirty years, a number of devices have been proposed for both clamping and cutting the cord in an abbreviated procedure, although few of them have been used commercially. For example, U.S. Pat. No. 3,323,208 to Hurley, Jr. shows an umbilical cord clamping device which includes two clamps held in side-by-side positioning by pins on one clamp which frictionally fit into holes on an abutting edge of the other clamp. A blade is positioned between the clamps and cuts the cord as the clamps are closed on the cord. However, the short pins of the clamps do not reliably hold the clamps together such that accidental separation is prevented.
U.S. Pat. No. 3,631,858 to Ersek discloses another cutting and clamping device. The device includes two clamps held together side-by-side by a frangible connector. A cutting blade is coupled to one of the arms of a clamp such that when the clamps are closed on an umbilical cord, the blade first severs the cord and then breaks the connector, thereby separating the clamps. However, the device is somewhat difficult to operate, due to the high force necessary to break the connector.
U.S. Pat. No. 4,026,294 to Mattler shows an umbilical cord clamping device that includes two clamps attached by a frangible connection to the cutting blades of a scissors-like applicator device. Initial squeezing of the handles of the applicator device closes the clamps around the umbilical cord. Further squeezing breaks the connectors to separate the clamps from the cutting blades. However, this device is relatively complicated to set up and use, and requires many parts, including a separate relatively expensive installation device.
U.S. Pat. No. 4,716,886 to Schulman et al. shows a device having two clamps held side-by-side with a shear pin, and a blade slidably positioned between arms of the clamps. The movement of the blade between the arms is impeded by the shear pin. The clamps are closed upon an umbilical cord by pressing the blade downwardly. After the clamps are fully closed, the shear pin is broken by further pressure upon the blade, so that the blade is moved inwardly to sever the umbilical cord. However, the device is difficult to operate, due to the need to break the shear pin. Another more recent patent to Schulman et al., U.S. Pat. No. 4,938,215, discloses a similar device.
U.S. Pat. No. 4,781,188 to Collins discloses an umbilical cord clamping and cutting device that includes two spaced apart clamps positioned within clamping applicator. Closing the applicator simultaneously closes the clamps. A blade is attached to one arm of the applicator, such that when the clamps are simultaneously closed on the cord, the blade automatically cuts the cord. The applicator is then opened and separated from the clamps which remain closed over the severed ends of the cord. The device uses a relatively large number of parts.
U.S. Pat. No. 4,856,517 to Collins et al. discloses a similar device that includes two clamps positioned within an applicator. The clamps are locked in a closed position about an umbilical cord by a latch. A knob having a blade is fitted within a slot in the applicator and is manually moved forward to sever the cord with the blade. When the knob reaches the end of the slot, the latch is engaged and released by the knob to allow the opening and removal of the applicator, leaving the clamps fixed around the umbilical cord. The device requires two steps to operate; first, clamping the cord and, second, moving the blade. Furthermore, the device has a relatively large number of parts, making manufacture of the device relatively expensive.
Each of the above patents pose serious drawbacks in their use and manufacture. First, as discussed above, many require the use of multiple steps, and/or are difficult to operate, and/or require the breaking of pins or frangible connections, and/or require the use of application devices. Second, the devices tend to have a large number of parts, making their manufacture expensive and complex.
Co-owned U.S. Pat. No. 5,584,840 to Ramsey et al. proposes a solution to the shortcomings of previous devices. Ramsey et al. discloses a device including two clamps friction fit in a side-by-side abutting relation, with a blade coupled between the clamps. Each clamp includes a molded outer guard. Using only two fingers of a practitioner, the arms of the clamps may be brought toward each other, such that the guards enclose and hold fast a section of umbilical cord, the blade projects into a space between the two clamps severing the cord, and the interior serrated surfaces of the clamps provide clamping action. After the cord is clamped and severed, the two clamps may be easily separated using the same hand which operated to close the device, with one clamp remaining on the umbilical cord of the infant and the second clamp with blade attached being discarded along with the placenta. The Ramsey et al. device is not only easy to operate, but is very easy and inexpensive to manufacture as it comprises only two molded clamps and a blade.
Though the device of Ramsey et al. offers significant improvements over the prior art, clinical tests suggest that the stability of the device is not ideal during the cutting process.